Caribbean Reef Shark

(Carcharhinus perezi)

The Caribbean Reef Shark is no stranger to divers of the
Florida-Bahamas-Caribbean region. It is one of the most abundant large sharks in
the area, especially on outer parts of coral reefs, often participates in
organized shark feeds in the Bahamas. As a result, the Caribbean Reef may be one
of the most frequently photographed of sharks.

Well photo-documented it may be, but the Caribbean Reef Shark is often
mistaken for other species. It can be easily distinguished from Blacktip Sharks
(Carcharhinus limbatus), which sometimes mingle with Caribbean Reefs at
shark feeds, because Blacktips have a higher and more acutely sloped ‘nape’
(back of the head, above the gill region), distinct black tips on the pectoral
fins and lower caudal lobe, and the tip of the anal fin is white. Large, robust
individuals are often misidentified as Bull Sharks (Carcharhinus leucas),
from which they are most readily distinguished by the Bull’s shorter snout (less
than the mouth width) and broader first dorsal fin. The Caribbean Reef Shark is
most similar to the Dusky (Carcharhinus obscurus) and Galapagos (Carcharhinus
galapagensis) sharks, but divers are unlikely to encounter them within its
range. (See the
carcharhinid identification page.)

Just the Facts:

Maturity: unknown for
either sex, but probably about 7 to 9 yearsMode: placental viviparityGestation: unknown, but probably about a
year; females may take a year off between pregnancies to re-build
their energy storesPups: 4 to 6, alternate years

Diet:

Juvenile: crabs,
shrimps, and small bony fishes

Adult: a wide variety of bony fishes and
probably also rays and large invertebrates

Distribution: Western North
Atlantic, from Cape Hatteras, North Carolina east to Bermuda (Caribbean) and
south to southern Brazil (Amazonian)

Danger Rating: ** According to the
International Shark Attack File, 22 attacks are attributed to this species,
of which 11 were provoked and none were fatal.

Remarks: this is the most common
large shark of the Florida-Bahamas-Caribbean region and a regular
participant in organized shark feeds in the Bahamas. Despite this species’
abundance and the fact that it is fished commercially, astonishingly little
is known about its basic life history.

Caribbean Reef Sharks first attained a kind of fame as the “sleeping
sharks” of Isla Mujeres, off the Yucatan Peninsula. They were featured in
the April 1975 issue of National Geographic magazine (under the scientific
name Carcharhinus springeri), in which Genie Clark investigated how
and why these sharks slept in underwater caves. Although it had been known
that certain lethargic sharks – such as the Nurse (Ginglymostoma cirratum),
Pacific Angel (Squatina californica), and Spotted Wobbegong (Orectolobus
maculatus) – could rest motionless on the bottom for extended periods,
the Caribbean Reef Shark provided the first evidence of an active shark
doing so. Inside the caves, the sharks lay quietly on the bottom, actively
respiring 20 to 28 times per minute. Clark discovered that the sharks are
not really asleep, but that their eyes follow divers in the cave. Tests
revealed freshwater upwellings from the mainland, which may loosen the grip
of parasites and perhaps produce a narcotic effect the sharks enjoy.
Unfortunately, the famous “sleeping sharks” of Mexico have been pretty much
fished out now, victims of that country’s need for marine protein to feed
its hungry masses.

Caribbean Reef Sharks are unaggressive toward divers in most contexts.
Indeed, those that have been acclimated to the presence of divers by regular
organized feedings, seem to regard divers as more-or-less irrelevant, being
neither food nor threat. As such, diver-inured Caribbean Reef Sharks often
approach quite closely during organized feedings, providing terrific
opportunities for photography and videography. But the prudent diver bears in
mind that these are large, toothy wild animals capable of inflicting serious
injury. During organized shark feeds, you should keep your hands tucked under
your armpits or otherwise still and close to your body, as competing sharks may
mistake your flashing palms and fingers for a piece of bait and you could very
easily be bitten by accident. The Caribbean Reef Shark can become highly
stimulated and aggressive when spearfishing is taking place in its presence and
the species has been implicated in 11 attacks on divers. None of these attacks
were fatal but most – if not all – were probably avoidable.

Although this species does not announce its readiness to attack as blatantly
as the Indo-Pacific Grey Reef Shark (Carcharhinus amblyrhynchos), it does
signal it is feeling stressed or threatened. If a Caribbean Reef Shark you are
watching suddenly switches from serene cruising to short, jerky movements,
punctuated by frequent changes in direction and repeated dips of both its
pectoral fins: beware. If you are underwater, remain at or near the bottom.
Maintain eye contact with the animal and slowly increase the distance between
yourself and it. This should result in the shark easing its display or fleeing
the scene. The highly stereotyped nature of its display and rapid withdrawal
suggest that, under some circumstances, Caribbean Reef Sharks may regard divers
as potential predators or competitors.

As with so many aspects of its natural history, little is known about the
diet of the Caribbean Reef Shark. It is known to feed on Bigeyes (family
Priacanthidae), but – based on its narrow-cusped but finely serrated teeth –
probably feeds on a wide variety of other bony fishes as well as rays and large
invertebrates, such as octopus and squids. But, as Yogi Berra once put it, “You
can see a lot just by looking.”

I once was lucky enough to observe a 6-foot male Caribbean Reef Shark pursue
and eat a Yellowtail Snapper (Lutjanus crysurus) in an unbaited dive off
Nassau, Bahamas. The shark’s capture technique was fascinating to watch: rather
than ‘run down’ the snapper in a flat-out chase, it spiralled and wheeled in a
rather languid but focused manner, turning within half its own length to pursue
its prey. After several seemingly half-hearted attempts at catching the snapper,
the shark accelerated briefly, swung it’s head sharply to the left and caught
the fish neatly at the jaw corner. Was this, I wonder, like a boxer who feints
with his weaker arm – testing the reactions of his opponent – before delivering
the knock-out punch with the other? In any case, such observations of natural
predation are rare and I would welcome first-hand accounts from readers.

In recent years, organized shark feeds have provoked considerable
controversy. Critics claim that this activity changes the behavior of sharks and
the structure of reef ecosystems. There is concern that sharks become dependent
on these ‘hand outs’ and may associate all humans with food, increasing the
likelihood of attack. Proponents argue that sharks are simply opportunistic, if
the feedings stopped, the sharks would simply disperse and go back to feeding
upon whatever they fed on before. Although accidental nips have occurred (mostly
received by ‘shark wranglers’ conducting the feed underwater), there is no good
evidence that shark feedings increase the likelihood of attack away from the
feeding site. The issue of modifying reef ecosystems is more difficult to
assess. Yes, shark feeds may concentrate predators artificially and the
intensified removal of fishes from the environment for use as shark bait is a
concern. But populations of sharks and other reef predators have been seriously
depleted by overfishing and habitat erosion and many operators use left-over
scraps from local restaurants, using fish remains that otherwise would have gone
to waste. Clearly, this is a complex issue and a quick or easy resolution is not
on the horizon.

In my opinion, responsibly conducted shark feeds – complete with a good shark
biology and conservation message – are spectacular, educational, and reasonably
safe. Many divers who are already admire and are fascinated by sharks enjoy the
opportunity to observe and photograph them from close range. Divers who fear
sharks due to ignorance and inexperience come away from organized shark feeds
with a new-found respect and appreciation for these marvelous creatures. Not
only are they delighted they were not eaten, but they are invariably in awe of
their graceful lines and swimming movements. As the most frequent ‘dinner guest’
at organized shark feeds in the Florida-Bahamas-Caribbean region, the Caribbean
Reef Shark is a sleek, beautiful ambassador to sharkdom.